The promise and hazards of stem cell research

PORTSMOUTH — Dr. Amy Sievers, an oncologist at Portsmouth Regional Hospital, does stem cell transplants with great success for her patients and is a firm advocate for stem cell research.

Karen Dandurant

PORTSMOUTH — Dr. Amy Sievers, an oncologist at Portsmouth Regional Hospital, does stem cell transplants with great success for her patients and is a firm advocate for stem cell research.

Sievers is allowed to do stem cell blood transplants because she does not use the source of controversy, embryonic stem cells. Instead, she can use stem cells from bone marrow, where blood is made. The cells can become new blood for transfusion into patients with blood-related cancers like leukemia.

"When we get past the chemo and radiation, the hope is we can replace blood and give the patient healthy blood and a chance to build a good immune system," Sievers said.

Parents saving cord blood when they give birth is an option, but Dr. Alexandra Bonesho of Core Physicians in Epping said it is very costly for the patient, is not covered by insurance and is not something pediatricians recommend widely unless there is a reason.

"It's not something we use as a practical course of events," Bonesho said. "Cord blood banking is very expensive, less so if the blood stem cells are donated to the National Cord Blood Bank. In most cases, the chance that you will need it for your own child is unlikely, unless there is already a known condition in the family."

For example, if there is a history of leukemia in another child, it may be worthwhile. Bonesho said in a case like that, having the baby's own blood stem cells can be the perfect answer.

"However, chances are good that if there is a sibling, they may also be a good match if a bone marrow transplant is needed," Bonesho said. "However, transplants are not the normal course of treatment in children with leukemia."

That being said, the cord blood could eventually be used for research in the future to find a cure for diseases like sickle cell anemia, Bonesho said.

Federal funding for much stem cell research is blocked mainly over the opposition to using embryonic stem cells. The cells come from blastocysts (fertilized eggs) from an in-vitro facility. The blastocysts are excess and are usually donated by people who have already been successfully treated for fertility problems.

"Cord blood is not the same," Bonesho said. "It does not involve using an embryo. If not used, the cord blood is discarded, so we are talking about the use of something that would otherwise be wasted."

The controversy arises over the question of when life begins. Is a fertilized blastocyst a human life?

Proponents argue the embryo can serve a noble cause, advancing medical research because embryonic stem cells are totipotent. That means they are undifferentiated and can potentially be developed into any type of cell. It is this property that could allow a single fertilized egg to develop into an entire person, with all the necessary organs and functions needed to support life. The possibility of growing new organs like a heart to replace a damaged one, or curing cancer and other diseases, is a strong argument for the use.

The question of whether moral or religious concerns should dictate such research is unlikely to be decided completely to either side's satisfaction. The issue was highlighted during the presidency of George W. Bush, when he enacted a ban on federal spending for stem cell research in 2001. He argued that the research would destroy human life. The ban also covered creating embryos for the purpose of using them for stem cell research (cell farming).

Congress lifted the ban in 2007, allowing the use of certain excess embryos after determining they are ones that otherwise would be discarded. Bush vetoed the bill. In 1993, the Clinton administration supported research and the funding ban was altered, with specific parameters set.

State laws can also set parameters for the use of stem cell research. In New Hampshire and Maine, there are restrictions on the storage time for using frozen embryos and on the sale or purchase of human tissue (including embryos) for research.

Instead, researchers are finding the best ways they can use adult stem cells and stem cells from umbilical cord blood.

"Adult cells have already differentiated to some level," Sievers said. "We can use bone marrow stem cells to make blood because that is what they do. Blood is made in the bone marrow."

Sievers said stem cells in the body already repair damage, as in the case of skin cells, which repair breaches in our largest organ. The limitation is that they are restricted to the function they have developed into by birth.

"Through the use of embryonic stem cells the possibilities are really exciting," Sievers said. "We could potentially grow a new heart or a spinal cord. We might be able to grow new nerves. Right now, a damaged nervous system, damaged nerves, often cannot be repaired, depending on how they are damaged."

Federal funding is restrictive right now, but Sievers said there are no restrictions on embryonic stem cells if a project is privately funded.

Cloning is a big part of the controversy, the fear that someone may clone a human being. Based on the cloning of Dolly, a sheep, Sievers said it could be done in theory but it is unlikely.

"There will always be people who do immoral things," Sievers said. "Most funded projects will be legally sound. There would be a strict vetting process. Projects would be informed choices made with moral choices for the good of everyone. At least I would hope so. I think the possibilities outweigh the objections.

"Even with unlimited access to totipotent cells, the uses are still very technically difficult in application," Sievers said. "It may be possible, but it will be very difficult to grow a heart. If we can grow a heart or heart muscle or other organs, we may be able to deal the problem of donor organs that can be rejected by the patient's own defenses."

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